1. FILED OF THE INVENTION
The present invention relates to a contact mechanism having electrical contact pieces, such as a relay or switch. More particularly, this invention relates to a contact mechanism having electrical contact pieces which are so arranged that a movable contact piece can surely and easily contact and separate from a fixed contact piece, while maintaining a wiping effect. Still more particularly, this invention relates to a contact mechanism with a semispherically-shaped movable contact piece which wipes and slides on a semispherically-shaped fixed contact piece.
2. DESCRIPTION OF THE PRIOR ART
With regard to the contact pieces of a current relay or switch, generally the movable contact piece and the fixed contact piece are formed to be of semispherical and flat shapes respectively. With contact pieces having the structure described above, the contact piece is frequently welded to the contacted side by an arc. Also, it is often moved and a high electrical consumption results, so that an insulating film is easily generated on the contact piece. In this case, the contact resistance is increased, exerting an adverse effect on the function of the device. Further, the centers of the conventional fixed contact pieces and the movable contact piece are provided on the same line. Therefore, when a semispherically-shaped moving contact piece wipes and slides on a semispherically-shaped fixed contact piece, the problem occurs, in which the above-described moving contact slides beyond the fixed fixed contact piece and cannot be separated.